There is no way to measure without sticking it in your pocket, as the "fit" will vary with the cut of the pocket and pants. Stick it in your pocket and draw vigorously without finess. Do NOT NOT NOT NOT NOT practice draw with your finger on the trigger. Build your motor memory with your trigger finger along the side of the gun as you draw.

Some recommendations:

Duluth Trading Company Ballroom Jeans. These are good jeans with heavy cloth used for the pockets. They help conceal, and will stand up to heavy use.

Stellar Rigs Kydex Pocket Holster. As thin as possible, and impervious to sweat.

Turn your pocket inside out when you wash your pants. Pocket lint is your enemy, and it is shocking how far it can work its way to inside your gun.